How to tell whether the shell is run in screen? For example, I run screen and it starts a bash environment. How to tell in the bash, whether it is run by screen or it is a normal bash environment?
It can be identified by checking the TERM environment variable:
In a bash in screen:
[zma@localhost ~]$ env | grep TERM
TERM=screen
TERMCAP=SC|screen|VT 100/ANSI X3.64 virtual terminal:
However, in a “normal” bash environment:
[zma@localhost ~]$ env | grep TERM
TERM=xterm
“In each window’s environment screen opens, the $TERM variable is set to “screen” by default.” — screen manual https://www.systutorials.com/docs/linux/man/1-screen/